Fix appearance of Views native overlay scrollbars for RTL.

Bug: 736539
Change-Id: I7ae1d4f48f613fb5b2526755d7282ced7f424b23
Reviewed-on: https://chromium-review.googlesource.com/567200Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485879}

ui/views/controls/scrollbar/overlay_scroll_bar.cc

@@ -38,6 +38,7 @@ OverlayScrollBar::Thumb::Thumb(OverlayScrollBar* scroll_bar)
 OverlayScrollBar::Thumb::~Thumb() {}
 
 void OverlayScrollBar::Thumb::Init() {
+  EnableCanvasFlippingForRTLUI(true);
   SetPaintToLayer();
   layer()->SetFillsBoundsOpaquely(false);
   // Animate all changes to the layer except the first one.
@@ -107,9 +108,10 @@ void OverlayScrollBar::Thumb::OnBoundsChanged(
 void OverlayScrollBar::Thumb::OnStateChanged() {
   if (GetState() == CustomButton::STATE_NORMAL) {
     gfx::Transform translation;
+    const int direction = base::i18n::IsRTL() ? -1 : 1;
     translation.Translate(
-        gfx::Vector2d(IsHorizontal() ? 0 : kThumbHoverOffset,
-                      IsHorizontal() ? kThumbHoverOffset: 0));
+        gfx::Vector2d(IsHorizontal() ? 0 : direction * kThumbHoverOffset,
+                      IsHorizontal() ? kThumbHoverOffset : 0));
     layer()->SetTransform(translation);
     layer()->SetOpacity(ui::kOverlayScrollbarThumbNormalAlpha);